This invention relates to an electronic apparatus for controlling the air-gasoline mixture supplied to an internal combustion engine.
Devices are known for feeding internal combustion engines with an air-gasoline mixture. Such devices normally comprise a sensor for sensing the exhaust gases and for providing signals corresponding to the strength of the air-gasoline mixture at a rate of about the stoichiometrical ratio; a plurality of sensors of characteristic magnitudes for sensing the engine operation and external environment and for providing signals corresponding to these magnitudes; a governor device for the strength of the engine feed air-gasoline mixture; and an electronic device having applied thereto both the signals supplied by the exhaust gas sensor and the signals supplied by the sensors of the engine and external environment characteristic magnitudes, the electronic device controlling the air-gasoline mixture governor device as a function of such signals, so as to obtain predetermined operating conditions of the engine.
A drawback of the prior art devices are that they are capable of detecting the air-gasoline mixture strength, by way of the exhaust gas sensors, only within a narrow range about the stoichiometrical air-gasoline ratio.
This limitation is a result of the fact that the chemical-physical conditions required to enable the sensors to detect univocally the values of the air-gasoline ratio only occur with mixtures having such ratios.
Thus, the prior art devices can control the feed of internal combustion engines only with mixtures having an air-gasoline ratio equal or close to the stoichiometrical value. As a result, these prior art devices are unfit for feed control where it is required to feed the engine with mixtures having an optimum air-gasoline ratio different from the stoichiometrical ratio to provide determined performances. For instance, it may be necessary to feed an engine with leaner or richer mixtures in order to obtain maximum power, minimum consumption, low pollution or, finally, compromises of these and further performances.